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Tomatoes 2008
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Have you been longing for a greenhouse of your very own but held back because of high operations costs? Or perhaps you already have a greenhouse but have practically closed it down because the heating bills were out of sight? Or maybe you love butter crunch lettuce and spring season is too short? Whatever the reason you have for wanting a change around your house, you have company - lots of company. Some years ago we obtained a kit for a small greenhouse that my husband with my help erected in the back yard. The price was modest and erection was simple but there were problems. Our low humidity and hot summers were not compatible with sealing system of this little greenhouse, so we added wooden strips to seal the seams. The summer sunshine made the greenhouse unbearably hot from April to October so another vent went high up at the peak. That helped some, but from June to September the greenhouse stood empty except for the baby tears, wandering Jew and paper white narcissus growing in the soil floor. As the years passed, it became more and more apparent that there had to be a better greenhouse. Then came the energy crunch, and the soaring electric bills make it imperative that we must either have something new or give up growing all those plants I enjoyed so much. I wrote for catalogs from all the greenhouse companies I could find. When the catalogs came, I read all of them carefully - construction, cost, size, etc. I also read all the books I could find on solar greenhouses and solar homes. Gradually I began to formulate some plans of what my greenhouse was to be. None of commercially made greenhouses had what I wanted. It had to be solar heated, a passive system. It had to have a dirt floor under the benches, it had to fit in the small space between the house and the lot line on the south. With all of this in mind, I had a problem getting someone to build the greenhouse. Plans were to be drawn up for me by one party. Having never built a greenhouse before, however, they borrowed all my catalogs for reference. I waited and waited for an estimate that never came (and I never saw my catalogs again.). Then a friend suggest that her husband might do it. We met for a discussion of what I wanted. More time passed. As I became impatient, word was received that he couldn’t do it for me. So, I was back to square two: ideas, but no one to carry them out. My husband isn’t the original handy-man. In fact, in the years past, if the washing machine broke, I was the one who tore it apart and got the new parts, and fixed it. However, he volunteered to be my architect, my construction engineer and carpenter if I would give him the details of what I wanted. My requirements were; it must be as insulated as possible - double glazing, doubly insulated foundations, heavy insulation in both end walls and the half roof. In addition, the south wall must be a 55 degrees, the optimum angle for the sun to heat it during the winter at this latitude. He set to work figuring out all the rafters and beams, calculating the number of 2x4’s and the length needed, kind of nails and how many; how much sunlite plastic glazing, the best caulking material. The first step of actual construction was, of course, the foundation. He broke up the cement of the drive that he had put in several ears previously, he then measured, built forms and began mixing cement. Before setting the bolts, he remeasured and checked to be sure the foundation was square. Once the foundation was set, the forms were removed and Styrofoam sheets were placed on either side of the foundation to insulate the floor from the cold ground outside. Soil was then filled in around the sheets and watered down. Construction was to be of redwood, one reference source said red wood was durable enough not to need treating with a wood preservative. Two pages later the same reference said redwood should be treated. The old greenhouse had been redwood, and it was falling apart with rot, so I decided we should treat every board. Copper naphthanate was the recommended preservative, it is effective and not-toxic, I called the lumber yards and paint stores. They had never heard of it. They said I should use “penta” or the creosote derivative penta clorophenol. But penta is very toxic to both plants and people. The wholesale salesman tried to convince me that copper naphthanate was really just another name for “penta”. I called a company whose business was building greenhouses. They gave me the name of Cuprinal which apparently was originally copper naphthanate but was now tri-butyl tin. I was able to find a source of this and work proceeded. My job was painting every 2x4 on every side, including the cut end. When they were dry the framing of each side, knee wall, end wall and two roof sections were nailed together into units. This was done on the lawn in the back yard. The large beam was pieced together. One sunny day, we were ready to put it all together, I wondered if the two of us could put it up and raise the big center beam without doing bodily harm to either of us. We did it. The side walls were put up first and fastened down with bolts, then the knee wall which was bolted to the end walls, the center beam was then placed in the pocket in the two end walls. Lastly the framing of the roof was lifted into place and bolted down. It was a bit wobbly at first, but as the sheathing on the sides went on, it became solid and sturdy. The glazed roof section was put in place with a generous bead of silicone caulking at every juncture. At last the greenhouse was fully enclosed, I put a maximum-minimum thermometer inside the as yet uncaulked, uninsulated area. The temperature inside the greenhouse was 36 degrees that night although the outside temperature dropped into the teens. The second night the greenhouse temperature dropped to 38 degrees, the third night to 42 degrees. It was quite clear that the solar feature was working effectively. The only heat storage area was the soil under the benches, the cement walkway and the stucco wall of the house. I was thrilled! Many plants could be grown in a cool greenhouse. Work seemed to go very slowly from then on. All seams were filled with Fiberglas and caulked. Insulation was place in all the solid walls, interior walls were covered with tempered Masonite. The roof was covered with tar paper and shingles. Although next to the house, the greenhouse is not attached to the house, it was designed this way so that, if at some future time we wish to move or remove the greenhouse, it can be unbolted and taken apart in sections to be reassembled elsewhere. In January there was a very cold spell. Some of the plants in the old greenhouse were frozen when the heater was out one night. A few days later, I began moving what was left into the new greenhouse, I improvised some benches with cement blocks and as I removed the plants from the old greenhouse I pulled out those benches, I was greeted by an array of twenty-six paper white narcissus bloom stalks under one bench. What a lovely surprise and good omen! Racks were built against the house for water storage container to store the sun’s heat for the dark cold nights. I began filling them with gallon milk cartons of water. The most efficient stacking method was on their sides, but they leaked at the caps. I sealed the caps with silicone caulking and painted them black with acrylic paint for better heat absorption. Something in the acrylic paint weakened the plastic at the seams, and they began to split at the bottom. All my friends were saving milk cartons for me because I needed 250 or more. As they became available, I switched to five gallon paint cans and later to metal drums. In all over 300 gallons of water is stored on the north wall. One serious problem remained which we weren’t sure we had solved. What would happen during the summer? Would I have to move all my plants to the patio to protect them from the intense weather? We waited for spring. Then suddenly, in April, it was as if someone had turned off the sun. No longer did the temperature climb above 100 degrees during a sunny day. The climbing sun struck the 55 degree south wall at an angle so much of the light was reflected harmlessly off the outer glazing, the insulated half roof shaded the entire north wall.., and the greenhouse stayed cooler. By mid-June the vents were both fully open day and night and cool air from the swamp cooler in the house flowed through the open window. The temperature in the green house was never any warmer than the outside air and was usually much cooler. All the plants, except geraniums and others I normally plant outside in the ground, remained in the greenhouse and grew and bloomed as they never had before. Benches were designed and installed in the greenhouse. They are redwood frames topped by a removable panel of wire mesh to let light and air reach the soil below. Hooks were added for hanging baskets. Everything needing shade was moved to the north wall. Roller shades were put on the outside in further shading was needed. I am still am still happily surprised by the way it works, we have added a window fan on a thermostat that turns the fan on when the greenhouse reaches 80 degrees. The fan blows the warm air into the bedroom cutting down on the heat needed in the house. At night I can sleep under the window and the fresh, oxygen laden flower scented air flows in from the greenhouse and refreshes me. The furnace humidifier has been turned off because the house humidity was climbing above 60%. Now the humidity ranges from 45 to 55% almost ideal for me. Cold air from the house returns to the greenhouse by way of a vent near the floor. Is there anything I should have done differently? Yes. First: we should have begun work sooner. Second: if we had a south door, I could have an inside entrance. As it is, I must go outside to get to the greenhouse. However, the window is there for my early morning viewing. Third: I would like to have a water line into the greenhouse, some day when we put in a sprinkler system that will be included. Until then the water stored in the containers is always available for a quick soaking. Fourth: I need a better lighting system for nighttime visits. Electricity is available from the bedroom, but so far I am using a drop cord. Along with cacti, geraniums and paper white narcissus, the greenhouse has contained bougainvillea’s, baby tears, pepperomias, marguerites, clerodendron, Swedish ivy, hoya, asparagus fern epiphyllum, kalanchoes, agapanthus, begonias, gardenias, camellias, impatiens and much more. It may sound as though there is a lot of room in an 8x14 greenhouse, but if fills up quickly as little plants grow into big ones. A lot of cuttings can quickly fill even a large greenhouse, if you want to build your own greenhouse , my husband knows all about it! |